As portable electronic devices become more compact, and the number of functions performed by a given device increases, it has become a significant challenge to design a user interface that allows users to easily interact with a multifunction device. This challenge is particular significant for handheld portable electronic devices, which have much smaller screens than desktop or laptop computers.
One important aspect of measuring a user interface's user-friendliness is whether the user interface accepts different types of user actions that correspond to the same function. Different users can choose different user actions based on their own preferences or habits. One user can choose different user actions at different times depending on which user action is more convenient than others at a specific moment.
But many conventional user interfaces, such as those that include physical pushbuttons, often have no such inflexibility. All users have to interact with the user interfaces in a specific manner to get desired results whether or not the manner is contrary to most users' preferences or habits. When coupled with the time consuming requirement to memorize these specific manners and the difficulty in activating a desired pushbutton, such inflexibility is becoming increasingly frustrating to most users.
Accordingly, there is a need for portable electronic devices with more flexible and intuitive user interfaces that perform similar operations in response to different finger gestures.